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RT or SBRT if the lesions were not active in the PET/CT?

Hi All,

As my last post about my father update, the Scan was wonderfull, our doctor suggest traditional RT to the lesions after finish the 6th cycle of the gem+abrax and then have a break. I know my father condition not yet count as remission, even the scan couldnt detect any active hyper metabolic lesions, because the CA19-9 still high.

My father miss his chemo treatment this week due to low white blood cell, but the doctor insist that neupogen not necessary needed atm, he just advise my father to delay the chemo to next friday.

What I want to discuss is "Can RT or SBRT being used when there are no lesions active on the scan? " Our doctor said that he can use the old scan to do the RT, but I try to get 2nd opinion from other onco, they said that they only do RT to the lesion based on the Scan.

Traditional Rt usually involves treating a broad area of the abdomen with radiation. It is used when there are no definite targets, or when multiple small targets are suspected.

SBRT is usually used when they have a very well defined target that they can precisely hit with the beam.

You can think of RT as being like a shotgun. It will hit everything in a large area, but it will also do more damage and cause more side effects. SBRT is like using a rifle. It will hit a small target and (hopefully) do very little or no damage to the surrounding tissues.

This is just a guess, but with no hypermetabolic areas showing and a high CA19-9, they may suspect several small areas too small to show up on a PET image. The problem is that an elevated CA19-9 can also be caused by inflammation.

One thing you could ask about is a chemo break to see if the CA19-9 slowly drops or rises. If it drops, some irritation causing inflammation might be the cause. If it rises, then therre is probably tumor growth. Obviously, this would have the risk of progression while on the break, but it would also give your father a chance to recover a little from chemo. They might want him to resume chemo (something like Xeloda) since it can sensitize the tumor to radiation effects.

There are no easy answers, just too many variables. All you can do is get the most information from his Drs about his specific case, talk to your father about what he wants, and make the best decision you can.

If the elevated of CA19-9 cause by the inflammation, then by stopping the chemo, the number will go down right? And if continue the chemo treatment, the number will raise back? My father ca19-9 will going down when doing chemo, so if this is case, mean that the PET/CT just unable to catch the lesions cause too small?

Another question is , if using the traditional RT, let said that some of the pancreas normal tissue damage, can it cause diabetes?

We all react so differently to chemo and radiation. I had traditional RT to pancreas 15 months ago and it did not cause diabetes. The radiologists do careful planning prior to RT to maximize benefits and minimize damage. My only side effect was mild nausea.

Dad has been struggling. He has lost weight - now at 55 kgs (from 70 kgs at diagnosis, so lost about 15 kgs / 33 lbs). He just completed his 6th cycle (12 infusions) and the oncologist, seeing as he has lost as much weight and some fluid built up, decided to give dad a chemo break for a month. I am not sure though why the onco decided to also hold off scans for a month. (His reasoning, I am told, the 6th cycle just completed a week back, so lets give it some time to show results? I thought everyone was screened monthly or once in 2 months on schedule?)

Same here Leon, my father onco also told that need to give my father chemo break, but after the RT. My father next scan will be after he finishing his 6th cycle, so 1 scan per 2 cycles, but for the next scan we will performing CTscan instead of PET/CT to find out what cause the pain at the left side of the abdominal, doctor suspect it was the tumor, but at the scan cant see anything, but there is a swelling on the pain area, I try to ask the doctor about the hernia, he said this is not hernia.